The main objective of this study is to thoroughly assess the effectiveness of systematic desensitization as a treatment technique for asthma. Accordingly, we included in the study: (1) frequent and objective measurement of pulmonary functioning; (2) high rate observations of asthmatic symptomatology; (3) regular objective observations of asthma-related behaviors; (4) continuous monitoring of all medications given for asthma; (5) the use of different therapists; (6) means to compare all changes against stable pre-therapy baselines; (7) comparisons of treatment subjects against carefully matched, non-treated controls; (8) a test of the durability of effects during a three month followup period; and, (9) the maintenance of essentially equivalent non-therapy enviornments for all subjects before, during and abter therapy.